Such a filling device has become known from West German Offenlegungsschrift No. DE-OS 37,20,326.
The prior-art filling device consists of a flexible tube-like delivery line, which has a coaxially led filling canal and breather canal. At the end of the filling device that is to be connected to a reservoir there is located a screw cap as a connection piece to the connection opening of an anesthetic reservoir, which may be, e.g., a glass bottle that is filled with liquid anesthetic. When screwing the screw cap onto the connection opening of the opened reservoir, the canals immerse into the storage bottle. A sealing washer at a stop of the screw cap is pressed against the end face of the neck of the bottle, and thus it closes the reservoir and establishes a gas-tight connection between the reservoir and the filling device against the surroundings. With its bottle-side opening, the filling canal remains in the gas phase located above the liquid even when the filling device has been put in place tightly, and the breather canal immerses into the liquid anesthetic in the vicinity of the bottom of the bottle. To fill an anesthetic vaporizer with the liquid anesthetic, the reservoir is raised to the extent that the liquid anesthetic will penetrate into the filling canal under the effect of the force of gravity, and the amount of gas displaced from the anesthetic vaporizer will flow through the breather canal into the reservoir.
It proved to be disadvantageous for the filling process that considerable amounts of anesthetic vapor are released even during the opening of the reservoir to connect the filling device, and that small amounts of liquid anesthetic may be spilled in the case of careless handling of the opened reservoir. It is also possible that larger amounts of liquid anesthetic will run out when the opened reservoir is knocked over. Especially in the case of low-boiling point anesthetics, considerable amounts of anesthetic vapor will form, and they will escape into the surroundings if the reservoir is open.